Design And Implementation Of Vehicle Terminal Timing And Frequency Calibration

Timing and frequency calibration system application in the field of communication, electric power, vehicle terminal, scope is very broad. This paper based on the background of Hebei University of Science and Technology satellite application center vehicle terminal design project, to the satellite module in the vehicle terminal of timing and frequency calibration system for key research. Timing and frequency calibration system can improve the time precision and frequency signal benchmark, meet the growing demand of modern science and technology to the time precision and frequency signal benchmark. This paper’s work from two aspects of hardware and software, using of FPGA(field programmable gate array) to build the timing and frequency calibration system with low cost and high reliability, high accuracy, the key proposed is PID filtering algorithm for the simulation research. By setting different timing accuracy, setting get the different coefficient of PID proportion, integral and coefficient, and setting different DA converter digits, different PD quantitative digits, and then to Matlab simulation, to compare the results, illustrates the influence of the parameter set to local second signal error precision. Through the Allan variance to compare and determine the crystal oscillator stability index, the results show the PID algorithm can well meet the design accuracy requirements, get the local second error index more than 1e-7, and the crystal oscillator stability reached the design requirements of 1e-8, it can well implement timing and frequency calibration, provide a good help for navigation and positioning.